Cow colon

Cow colon is the first part of the large intestine, which consists of three main sub-segments. Its diameter is slightly higher than the cow’s small intestine.

Both the small and large intestines are the major parts of the cow’s digestive system. Here, I will describe the anatomy of the cow’s colon with the hand-drawing diagrams and real pictures.

Quick answer: Cow colon extends after the cecum, whose anatomy is described by its location along with the features of its 3 main divisions.  

Thus, I will focus on the identification and features of the 3 main divisions of the colon, along with their subdivisions.

Where is the colon in a cow?

Figure 1 presents the schematic diagram/presentation of the large and small intestines from the cow’s abdomen. This hand-drawing schematic diagram presents the extension of the cow’s colon.

Here, the figure shows that the colon begins as a direct continuation of the cecum at the ileo-cecal orifice. Except for the first and terminal parts, it is arranged  in double elliptical coils between the layers of mesentery.

Figures 1 and 2 also show that the cow’s colon runs ventro-cranially, caudally, and cranio-dorsally. Thus, its location greatly varies within the abdominal cavity.

Figure 2 highlights the extension of the cow’s colon in the abdominal cavity. It also shows the direction of the colon’s courses.

However, you may state the location of the cow’s colon as follows –

Location: The cow’s colon extends from the cecum to the terminal part of the large intestine. Here, most of the cow’s colon is located at the dorsal aspect of the right side of the abdominal cavity, enclosed by the common mesentery.

Cow’s colon length in meters

The length of the cow’s colon may vary within the species. However, the average length is about 10 meters in a medium-sized cow.

Again, the diameter of the colon at its first part is the same as that of the cecum. But, it diminishes to about 5 centimeters in the course of the proximal loop (Figure 3).

Here, Figure 3 provides the basic concept of the length and diameters of the cow’s colon. However, it also shows differences in the diameters between the first part and the proximal part/loop of the colon.

In small ruminants (sheep and goats), the length of the colon is about 4 meters. However, the diameter of the sheep and goat’s colon is about 2 – 2.5 centimeters.

Capacity of the colon: The cow’s colon has a capacity of about 6 to 8 gallons/25 to 30 liters.

Cow colon anatomy

So, what should you describe under the anatomy of the cow’s colon? Well, you should follow the following –

• First: identify the major divisions and subdivisions of the colon/parts of the colon, and
• Second: describe the surface and topographic anatomy of these divisions and subdivisions/ parts.

Here, Figure 4 presents an overview of the anatomy of the cow’s colon. It presents divisions/parts of the colon along with their topographic anatomy.

However, I made this figure of the cow’s colon using both hand-drawn and real images. This might help you to learn and identify the anatomical overview of the cow’s colon.

What are the 3 parts of the cow’s colon?

Figure 5 clearly presents the 3 major parts/divisions of the cow’s colon. However, it presents various subdivisions of the ascending colon.

So, according to the disposition, the cow’s colon divides into 3 main parts –

• First: ascending colon
• Second: the transverse colon, and
• Third: descending colon,

However, the ascending colon shows three major loops: proximal, spiral, and distal. They are named according to their positions and appearances.

Here, the spiral loop shows three coils: the centripetal coil, the central flexure, and the centrifugal coil.

Now, I will describe these divisions/parts of the cow’s colon separately with the hand-drawing and real pictures. So, let’s start with the ascending colon anatomy, which is the first part after the cecum. 

Cow’s ascending colon anatomy

Figure 6 highlights the three main loops of the ascending colon. However, it also presents the three coils of the spiral loop of the cow’s colon.

Proximal loop

It is the first loop and is separated from the cecum only by the ileocecal opening. However, it forms an S-shaped curve and is located at the caudodorsal portion of the right side of the cow’s abdominal cavity.

Topographic anatomy: After beginning from the ileo-cecal orifice, the proximal loop of the colon runs cranially for a short distance. It is just at the level opposite to the ventral parts of the last two ribs. Then it turns dorsally and caudally, forming an S-shaped curve (Figure 6).

However, it continues caudally in relation to the right flank laterally and cecum ventrally. Here, the proximal loop turns forward and runs parallel to the second part of the duodenum at the level of the second lumbar. However, it now turns backward and continues with the spiral loop of the colon.

Spiral loop

The spiral loop of the ascending colon is continued with the proximal loop and consists of the following –

• Two centripetal coils,
• One central flexure, and
• Two centrifugal coils,

Figure 7 highlights the centripetal coils, central flexure, and centrifugal coils of the spiral part of the cow’s ascending colon.

These coils and flexures are attached to each other by connective tissue and form a disc. However, it is located in the right lateral abdominal region of the cow.

Distal loop

Figure 7 also shows that the terminal part of the centrifugal coils passes caudodorsally on the proximal loop. However, it turns around the caudal border of the mesentery from left to right.

Finally, it runs cranially and medially to the proximal loop of the ascending colon. Here, the elongated part (marked in the diagram) is known as the distal loop of the ascending colon.

Cow’s transverse and descending colon

Figure 8 shows that the distal loop of the ascending colon continues cranially and joins with the short transverse colon. It passes from right to left around the cranial mesentery artery.

However, the transverse colon continues with the descending colon. Here, the descending colon runs caudally and dorsally to the ascending duodenum.

It inclines to the right just under the right kidney of the cow. However, it forms a sigmoid flexure near the pelvic inlet and continues caudally (Figure 8).

Here, the sigmoid part of the descending colon is attached to the sublumbar region by a short mesocolon.

FAQ’s on cows’ colon

Conclusion

So, the colon of a cow divides into ascending, transverse, and descending parts according to their deposition. Here, the anatomy of the cow’s colon comprises the features of different loops and coils of the ascending part.

However, the transverse and descending parts of the cow’s colon have specific features and locations. The cecum, ascending duodenum, proximal loop, and distal loop are adherent together by connective tissue around the root of the mesentery.

References

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